No one has ever mistaken me for an optimist. And yet, when I consider what is perhaps the most pristine source of pessimism—the moral development of our species—I find reasons for hope. Despite our perennial mischief, I believe that we have made unmistakable progress in our morality. Our powers of empathy appear to be growing. We seem to be more likely now than at any point in our history to act for the benefit of humanity as a whole.

Of course, the 20th century delivered some unprecedented horrors. But those of us living in the developed world are becoming increasingly alarmed by our capacity to do one another harm. We are less tolerant of "collateral damage" in war—undoubtedly because we now see images of it—and we are less comfortable with ideologies that demonize whole groups of human beings, justifying their abuse or outright destruction.

Taking a somewhat provincial example: racism in the United States has unquestionably diminished. If you doubt this, consider the following Los Angeles Times editorial, written in 1910, in response Jack Johnson's successful heavyweight title defense against Jim Jeffries, the so-called "Great White Hope":

A Word to the Black Man:

Do not point your nose too high
Do not swell your chest too much
Do not boast too loudly
Do not be puffed up
Let not your ambition be inordinate
Or take a wrong direction
Remember you have done nothing at all
You are just the same member of society you were last week
You are on no higher plane
Deserve no new consideration
And will get none
No man will think a bit higher of you
Because your complexion is the same
Of that of the victor at Reno

A modern reader could be forgiven for thinking that this dollop of racist hatred was printed by the Ku Klux Klan. Rather, it represented the measured opinion of one of the most prominent newspapers in the United States. Is it conceivable that our mainstream media will once again give voice to such racism? I think it far more likely that we will proceed along our current path: racism will continue to lose its subscribers; the history of slavery in the United States will become even more flabbergasting to contemplate; and future generations will marvel at the ways we, too, failed in our commitment to the common good. We will embarrass our descendants, just as our ancestors embarrass us. This is moral progress.

I am bolstered in my optimism by the belief that morality is a genuine sphere of human inquiry, not a mere product of culture. Morality, rightly construed, relates to questions of human and animal suffering. This is why we don't have moral obligations toward inanimate objects (and why we will have such obligations toward conscious computers, if we ever invent them). To ask whether a given action is right or wrong is really to ask whether it will tend to create greater well-being, or greater suffering, for oneself and others. And there seems little doubt that there are right and wrong answers here. This is not to say that there will always be a single right answer to every moral question, but there will be a range of appropriate answers, as well as answers that are clearly wrong. Asking whether or not an action is good or bad may be like asking whether a given substance is "healthy" or "unhealthy" to eat: there are, of course, many foods that are appropriate to eat, but there is also a biologically important (and objective) distinction between food and poison.

I believe that there are right and wrong answers to moral questions in the same way that there are right and wrong answers to questions about biology. This commits me to what philosophers often call "moral realism"—as opposed to anti-realism, pragmatism, relativism, post-modernism, or any other view that places morality entirely in the eye of the beholder. It is often thought that moral realism fails because it requires that moral truths exist independent of minds (it doesn't). Indeed, this worry partly explains humanity's enduring attachment to religion: for many people believe that unless we keep our moral intuitions pegged to the gold-standard of God's law, we cannot say that anyone is ever right or wrong in objective terms.

Consider the phenomenon of "honor-killing": throughout much of the Muslim world at this moment, women are thought to "dishonor" their families by refusing to enter into an arranged marriage, seeking a divorce, committing adultery—or even by getting raped. Women in these situations are often murdered by their fathers, husbands, or brothers, sometimes with the collaboration of other women. Is honor-killing wrong? I have no doubt that it is. But is it really wrong?

There seems to be no question that we are wired in such a way that love is more conducive to happiness than hate, fear, and shame are. If this is true, honor-killing would be wrong even if a majority of human beings agreed that it was right. It would be wrong because this practice (along with the intentions that give rise to it) reliably diminishes human happiness: it creates immense suffering for women and girls; it conditions men to feel that their personal dignity is predicated upon something that it need not be predicated upon; it deranges the relationships between men and women, making them far less loving and compassionate (and therefore a lesser source of happiness) than they might otherwise be. While these are claims about human subjectivity, they are also, at bottom, objective claims about the real foundations of human happiness.

All of this implies, of course, that morality is a potential branch of scientific inquiry—not merely that science will one day describe our moral judgments at the level of the brain, but that science may one day be able to tell us what is good (that is, it will tell us which psychological intentions and social practices are truly conducive to the deepest happiness).

Because I believe that moral truths transcend the contingencies of culture, I think that human beings will eventually converge in their moral judgments. I am painfully aware, however, that we are living in a world where Muslims riot by the hundreds of thousands over cartoons, where Catholics oppose condom use in villages decimated by AIDS, and where the only "moral" judgment that seems guaranteed to unite the better part of humanity at this moment is that homosexuality is wrong. Which is to say that I am here celebrating our moral progress while being convinced that billions of my neighbors are profoundly confused about good and evil.
I may be a bigger optimist than I thought.